Eichhornia crassipes biodiesel as a renewable green fuel for diesel engine applications: performance, combustion, and emission characteristics.

This work examines the feasibility of fuelling biodiesel derived from Eichhornia crassipes in a compression ignition engine. This work also proposes water hyacinth biodiesel (WHB) as a potential alternative energy source since the above species is available extensively in freshwater, marine, and aquatic ecosystems throughout the world. WHB was blended with petroleum diesel fuel at various volume proportions of 10%, 20%, 30%, 40%, and 100% and their properties were analyzed as per ASTM standards for its application as biofuel. The prepared test fuels were analyzed experimentally in a single-cylinder diesel engine at constant speed (1500 rev/min) for its performance, combustion, and emission characteristics. Test results projected that the characteristics of 20% WHB + 80% diesel fuel blend were in par with neat diesel fuel in terms of thermal efficiency, HC, CO, and smoke emissions. However, WHB blends resulted in slightly higher levels of CO2 and NOx emissions. At full load, the attained cylinder pressure and heat release rate of WHB were comparatively lower than diesel fuel. Ignition delay is lowest for B100 blend and therefore the diffusion burning phase of biodiesel phase is found to be dominant in comparison with diesel fuel. For biodiesel blends, the combustion starts earlier due to higher cetane number, lessened delay period, and lowered calorific value followed by lowered HRR. Graphical abstract.

An experimental assessment on the influence of fuel-borne additives on ternary fuel (diesel-biodiesel-ethanol) blends operated in a single cylinder diesel engine.

The present work is dedicated to the experimental analysis on the influence of fuel-borne additives on ternary fuel blend operated in a single cylinder DI diesel engine. Alumina (Al2O3) nanoparticles were chosen as fuel additives at dosing levels of 10, 20, and 30 ppm, respectively, and the ternary fuel (TF) is prepared by blending 70% diesel, 20% Jatropha biodiesel, and 10% ethanol. Performance characteristics like brake thermal efficiency (BTE) and brake-specific energy consumption (BSEC) and emission characteristics like HC, CO, NOx, and smoke along with combustion characteristics like cylinder pressure, HRR (heat release rate), and CHRR (cumulative heat release rate) were considered for analysis. Based on experimentation, it is observed that TF blended with 20 ppm alumina nanoadditive (TF20) resulted in higher BTE and lowered BSEC by 7.8 and 4.93% and lowered HC, CO, NOx, and smoke emissions by 5.69, 11.24, 9.39, and 6.48% in comparison with TF. Moreover, TF20 resulted in higher cylinder pressure, HRR, and CHRR of about 72.67 bar, 76.22 J/°CA, and 1171.1 J, respectively, which are higher than those of diesel and TF. Hence, it is concluded that the addition of 20 ppm alumina nanoadditive in TF can enhance the engine performance and combustion as well as lower the exhaust pollutants simultaneously.

Combined impact of EGR and injection pressure in performance improvement and NOx control of a DI diesel engine powered with tamarind seed biodiesel blend.

In the process of creating eco-friendly environment and conserving fossil fuels for the future generations, biodiesel has been chosen as a good substitute for diesel. It is a proven fact that biodiesel operated diesel engine can deliver comparable results with diesel. The present work focuses on TSME20 (tamarind seed methyl ester 20% + diesel 80%) as a renewable fuel, and its performance and emission results are analyzed at different exhaust gas recirculation rates and various injection pressures. The process is done in two stages. Firstly, experiments are conducted on TSME20 operated diesel engine at three injection pressures (180, 200, and 220 bar), and the results are analyzed. From the experimental results, improved efficiency by 2.29% and reduced emissions, such as hydrocarbon, smoke, and carbon monoxide, by 53.84, 56.25, and 75.15% are observed at the peak load for the increased injection pressure (220 bar) over 200 bar except NOx levels, which are found high by 11% compared to 200-bar injection pressure. Secondly, tests are again performed at the optimal condition of 220-bar injection pressure with the exhaust gas re-circulation (EGR) rates at different levels, i.e., 10 and 20%. The test results reveal that the addition of 10% EGR to the engine operating at 220 bar counteracts the release of NOx levels, which are found reduced by 80.5% over standard conditions without much compromise in engine performance. Also, the combustion characteristics of diesel engine at 220-bar fuel injection pressure of tamarind biodiesel blend showed enhancement when compared to other fuel injection pressures.

Improvement of ternary fuel combustion with various injection pressure strategies in a toroidal re-entrant combustion chamber.

The present experimental work focuses on the influence injection pressure and toroidal re-entrant combustion chamber in a single cylinder diesel engine fuelled with ternary fuel (diesel-biodiesel-ethanol) blend. Ternary fuel (TF) is prepared by blending 70% diesel, 20% biodiesel, and 10% ethanol blends and its fuel properties were investigated and compared with diesel fuel. Since the physic-chemical properties of TF are well behind the diesel fuel, it is proposed to be blended with 20 ppm alumina nano additives which act as an ignition enhancer and catalytic oxidizer. The resulting fuel mixture (TF + 20 ppm alumina additive) is named as high performance fuel (HPF). Experimentations were conducted on HPF subjected to various injection pressures of 18 MPa, 20 MPa, 22 MPa, and 24 MPa respectively and are operated in toroidal re-entrant chamber geometry (TG) at an injection timing of 22 obTDC. From experimentation, it was identified that, for TG-HPF, higher injection pressure of 22 MPa ensued highest BTE (Brake Thermal Efficiency) of 35.5% and lowest BSEC (Brake Specific Fuel Consumption) of 10.13 MJ/kWh owing to the pooled effect of higher swirl formation, improved atomization enhanced evaporation rate, and better air-fuel mixing. Emission wise TG-HPF operated at 22 MPa lowered the HC (hydrocarbon), CO (carbon monoxide), and smoke emissions by 18.88%, 7.19%, and 5.02%, but with marginally improved NOx (oxides of nitrogen) and CO2 (carbon dioxide) emissions by 3.92% and 3.89% respectively. In combustion point of view, it is observed that injection pressure increased the cylinder pressure, heat release rate (HRR), and cumulative heat release rate (CHRR) by 5.35%, 5.08%, and 3.38% respectively indicating improved combustion rate as a result of enhanced atomization, evaporation, and high turbulence inducement. Overall, it is concluded that operating the ternary fuel at 22 MPa injection pressure at toroidal re-entrant combustion chamber results in improved performance and minimized emissions.